Tech Talk #12 – Leaping to Conclusions

By David Reher, Reher-Morrison Racing Engines

At the 1968 Summer Olympics, gold medal winner Bob Beamon soared 29 feet in the long jump – a leap nearly 3 feet longer than the previous record. Beamon excelled in jumping across a sand pit – but if jumping to conclusions were an Olympic event, I have no doubt that a drag racer would win the gold.

Jumping to conclusions is an occupational hazard in racing. We want our cars to run faster, more consistently, and more successfully. The pressure to perform is intense, and often we allow our emotions to overrule our common sense.

During my days as a math student, I learned there is an important difference between a conclusion and an assumption. A conclusion is a judgment based on deliberation and reasoning; an assumption is a statement that is accepted without proof or demonstration. So when I hear someone make a statement like “that carburetor’s no good,” or “the torque converter is junk,” what I am usually hearing is really an assumption – an opinion stated as a fact.

It’s said that assumption is the mother of all screw-ups. I wouldn’t disagree, because the proof is all around us. For example, you arrive at the track and discover that the spare rearend is missing from the trailer. You hear yourself saying, “I thought you put it in,” while your partner replies, “I thought you did.” Both assumed something that wasn’t true – and now the gear ratio you need is sitting on a bench at the shop.

In my roles as an engine builder and a racer, I’m very familiar with the cost of jumping to conclusions. When an engine doesn’t perform properly, I run through a mental check list of possible solutions. It doesn’t matter whether it’s one of our own Pro Stock engines or a customer’s bracket motor – the troubleshooting procedure is always the same. Ignition system OK? Check. Fuel system all right? Check. Valve springs good? Check. But when everything is “perfect” and the engine still doesn’t run right, someone has obviously made a false assumption. If every component were functioning perfectly, there wouldn’t be a problem!

After decades in racing, I’m still learning how to avoid jumping to conclusions. I’ve seen brand-new batteries that were faulty, crank trigger magnets with reversed polarity, and carb floats that sank like stones. But just when I think I’ve seen it all, something new comes along.

We were dyno testing our race motor before the AutoZone Winternationals when it suddenly made one of those very expensive noises that usually means big trouble. “Dropped a valve!” someone declared. “Broke a pin!” said another. Everyone had a theory as we removed the heads and found an unfamiliar piece of metal in a cylinder. Then the conclusions flowed like a Texas flash flood: “You left the covers off the carburetors – that’s a bottle cap that went down the manifold.” We had at least 20 different explanations for the failure.

Finally we discovered the truth: A balance weight had come off one of the blades of the dyno room fan. That weight had stayed in place for 15 years and several thousand dyno pulls. It waited until we were testing our No. 1 engine before it got sucked down a carburetor venturi. Everyone felt a little sheepish when further inspection revealed several more loose weights on the fan blades.

The point is that we had jumped from faulty assumptions to erroneous conclusions. We hadn’t considered all of the facts before making a judgment. We wanted tidy explanations for the problem, so we invented them.

Racers want positive results, even if it sometimes requires jumping through logical hoops to reach them. When you invest the time and money to test, there is a strong predisposition to believe that you made progress – even if that belief requires a little self-deception. You really want to believe that gear ratio change or the new camshaft made a difference. But a week later when 35 cars are pounding down the same piece of asphalt, you may have to confront the reality that your test wasn’t valid and the performance improvement was imaginary.

Years ago I saw a sign on a garage wall that offered excellent advice: “When the results disagree with the theory, believe the results and invent a new theory.” Instead, we often distort the results to support a preconceived theory. A conclusion that is based on an emotional need will seldom improve a race car’s performance.

For thousands of years, it was accepted as fact that the sun and planets revolved around the Earth. Religion and philosophy supported the belief that man was the center of the universe, and complex theories were devised to explain the apparent motion of the heavens. But an astronomer named Copernicus theorized that the sun was really the center of the solar system – a view that ultimately knocked the foundation out from under the old view of the universe. Instead of accepting the popular assumptions, Copernicus used reason to arrive at a revolutionary conclusion.

Racing could use more people like Copernicus. Sometimes you need to see the world from a fresh perspective. I recently met an engineer who designs air conditioning systems for buildings. He uses very sophisticated solid modeling programs to manage airflow through a ventilation system. I realized that airflow through a duct isn’t fundamentally different from airflow through a cylinder head. I’m excited that the technology he uses might be adapted to our racing program. After all, I’ve developed plenty of preconceptions and assumptions in 30 years of racing. Now I may have found a tool that will give me new insight.

Reaching a valid judgement is hard work. It may be emotionally gratifying to decide “That’s the answer!” But I believe that it is more productive in the long run to say simply, “That’s interesting . . . that raises some questions.”

I will admit that there are days when I’m a world-class conclusion jumper. And I’ve known a few racers who could set Olympic records in leaping to conclusions. But I’m trying to train myself to think before I speak – and to examine every assumption before I accept it as truth.